1. Field of the Invention
The present invention relates to an equipment for measuring a difference in elevation between two points.
2. Description of the Prior Art
Measurement of difference in elevation is generally performed using a leveling pole and a leveling instrument, which is called a level. The leveling pole is set up at two measuring points, and its divisions are alternately read using a horizontally placed telescope comprised by the level. Then, a difference between the read values is obtained as a difference in elevation.
In addition, collimation cross hairs are arranged within a field of view of the telescope of the level. A horizontal distance can be roughly measured using two stadia lines affixed to the cross hairs at a predetermined interval. In this case, the distance between the stadia lines is read, and the horizontal distance is calculated according to a telescopic magnification.
In such conventional method of measuring a difference in elevation, since an operator reads the divisions on the leveling pole, it is difficult to realize a digital display. In addition, reading of numerical values in a data processor, data storage, and automatic data processing cannot be performed. The field of view of a telescope in a level is as narrow as 1.degree.20'. Therefore, digital numbers displayed on the leveling pole at intervals coarser than those of the divisions may fall outside the field of view, and a height value may be erroneously read. In a stadia measurement, since a horizontal distance must be obtained by multiplying a measurement value by a telescopic magnification, the calculation becomes cumbersome.